Portable toilet seat



FIG. 1 is a top perspective view of an ornamental design for a portable toilet seat;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a right side elevation view thereof;

FIG. 8 is a left side elevation view thereof; and,

FIG. 9 is a front elevation view thereof, showing the portable toilet seat positioned on a bucket.

The broken line showing of the bucket in FIG. 9 is for the purpose of illustrating environment and forms no part of the claimed design. 

CLAIM The ornamental design for a portable toilet seat, as shown and described. 